The best way to look after them is to keep them topped up with charge. The fewer and less deep the cycles, the longer they will last. They have no memory effect and therefore frequent charges are not detrimental to their performance. To maximise teir life, its best not to let their voltage drop below 12 volts however serious damage will not occur unless you let them go below 10 volts for any length of time, when sulfation occurs.

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What kind of voltage drop will happen when I put a load on the battery?

Depends on the load.

how low will the voltage go with a 10 amp drain on the battery?I would not expect anything more than a minor (0 - 0.5 volts) drop on a fully charged 30 Ah lead acid battery that is in reasonable condition.

Its probably a car type battery, I am no expert but I think you must keep it charged to 11 volts or so, or the lead or zinc in the plates starts desintegrating.

The deep cycle ones have something to avoid this, but it limits the current ?

Google deep cycle battery.

That battery is an SLA - and are typically used for UPS purposes; I am pretty sure most SLA batteries are "deep cycle". That said, all that's needed to be done is to keep it charged up, and not let it sit without periodic charging (or put it on a smart trickle charger to keep it topped up).

I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Supposedly, you should be able to get 10 amp continuously out of it for 3 hours, hence 30 amp/hour. Practically, it will drop in voltage over the period such that the device it hooks to will stop working at some point. These deep discharge batteries are tough and can take being discharged down quite a bit and not sustain damage; especially the AGM cells. You don't have to worry about adding water or it spilling when the robot flips over, but don't leave it on it's side or upside down for a long time; especially if it is charging. There is a vent on it somewhere to release gasses, and if it's upside down and charging, it may leak fluid due to gas pressure. Don't leave it fully discharged for very long (measured in days) or it will damage the cell.

Deeply discharged AGM batteries take a longer time to charge and require a lower charge current than 'regular' lead acid. If you check the manufacturer's web site (if you can find it) they will show recommended maximum charge current. The charge current is a function of cell area so it varies. Many AGM batteries recommend 13.4-13.6 VDC float to maintain charge and not damage the battery. You can find chargers that do this, or just get an lm317 and hook it up.

I got a 2 amp schumacher sc-200Athe guy at battery plus recommended it. I also have a smaller lead acid charger but it says .5 amps and only charge batteries smaller than 17 amps an hour.will the sc-200A charger be too fast?

That's a nice charger. I haven't used that particular one, but it has all the features you need to take care of the battery. Don't expect the battery to charge up quickly though; this kind of battery takes a charge far slower than it delivers. You'll have to experiment a bit to see how long it will supply power for you, but I think you'll like it.

Roughly you charge lead acid batteries at a rate no more than 1/10th their capacity for optimum lifetime. So your 30Ah battery would be charged at 3A. But the charge rate is not as important as avoiding discharging or 50% or leaving it sit off a charger for months at a time.

It's also worth noting that a sealed battery is charged to a different float voltage than a flooded (car) battery. Your charger offers no ability to choose the battery type; a slightly more expensive charger would.